Flexible polyurethane and polyurethane/polyorganosiloxane foam materials that absorb impact energy

ABSTRACT

A polyurethane foam, a polyurethane/polyorganosiloxane foam, and a polyurethane foam polyurethane/polyorganosiloxane foam material are disclosed and described herein. The materials are formed in the presence of a polymerization reaction initiator (an isoprenoid compound), and a polymerization reaction accelerator. The polyurethane foam is formed from an isocyanate and a polyol. The polyurethane foam polyurethane/polyorganosiloxane foam material comprises the polyurethane foam which is cross-linked to the polyurethane backbone to a polyurethane/polyorganosiloxane foam. Optional gelling agents, emulsification control agents, reinforcement fillers, cross-linkers, reinforcement polymers, rubber reinforcers, silk proteins, emollients, stabilizers and colorants are also described. The polyurethane and polyurethane-polyorganosiloxane foam materials exhibit a high degree of flexibility, resilience and excellent impact absorption.

RELATED APPLICATION(S)

This application is a continuation of U.S. Non-Provisional applicationSer. No. 14/477,521, filed on Sep. 4, 2014 and now issued as U.S. Pat.No. 10,138,373, which claims priority to U.S. Provisional ApplicationNo. 61/873,661, filed on Sep. 4, 2013, both of which are incorporatedherein by reference.

FIELD OF THE INVENTION

This invention relates to polyurethane foam and polyorganosiloxane foammaterials. The foam materials can be used in impact protective deviceswithin various environments such as, but not limited to include; thebumper of a vehicle, the doors of a vehicle, protective helmets,protective padding, groin cups and shoe soles. Accordingly, theinvention relates generally to the fields of polymer chemistry andpolyurethane/polyorganosiloxane rubber foams.

BACKGROUND

It is well documented that flexible polyurethane foam is produced from:a polyol, an isocyanate, water, a catalyst, and a surfactant. Polyol andisocyanate are mixed to form a polyurethane linkage. Water is present asa blowing agent and an aqueous medium. Additives, catalyst andsurfactant serve to promote nucleation, stabilization of the foamformation during the development stage, and improve foam properties forcommercial application.

Polyurethane properties in flexible foam are influenced by the types ofisocyanate and polyols used. The most commonly used isocyanates arearomatic diisocyanate or methylene diphenyl diisocyanate (MDI). Polyolscan be polyether polyols or polyester polyols. Polyether polyols aremade by the reaction of epoxides with an active hydrogen containingstarter compounds. Examples of polyether polyols, among others, are:propylene glycol, 1,3-butanediol, 1,4-butanediol, ethylene glycol,neopentyl glycol, 1,6-hexane diol, diethylene glycol, glycerol,diglycerol, pentaerythritol and trimethylol propane and similar lowmolecular weight polyols. Polyester polyols are formed bypolycondensation of multifunctional carboxylic and hydroxyl compounds.In addition to the polyether and polyester polyols, polymer polyols canbe used in flexible polyurethane foam to increase foam resistance todeformation. There are two types of polymer polyols: a graft polyol anda polyurea modified polyol. In addition, some polyols that existcommercially are natural oil polyols. These oleochemical polyols havegood hydrophobicity and exhibit excellent hydrolysis resistance,chemical resistance and UV resistance. With the presence of across-linker, these natural oil-based polyols (i.e. Sovermol® (BASF))form a polyurethane by linking with an isocyanate. Natural oil polyolsare polyfunctional alcohols based on renewable raw materials like castoroil, soybean oil and palm kernel oil, dipropylene glycol or glycerinwhich are often added as initiators to produce polyols for more flexibleapplications. Propylene oxide and/or ethylene oxide are then added tothe initiators until a desired molecular weight is achieved. The orderand amounts of each oxide affect many polyol properties such as watersolubility and reactivity.

In general, polyurethane foam is made using organic polyisocyanates suchas phenylene diisocyanate, toluene diisocyanate, hexamethylenediisocyanate, or 4,4-diphenyl-methane diisocyanate (MDI).

Flexible polyurethane foam is a common material used to protect objectsfrom impact forces such as in athletic activities, automotiveapplications, and boating applications. Such foams are lightweight andcontain small pores that allow foam to deform elastically under impactso that energy is absorbed and dissipated as the material is compressed.However, flexible foams can only be customized to respond to a veryspecific range of impact energies and hence generally cannot performwell across a wide range of impact types. A foam that is too soft for animpact will compress too quickly and transmit excessive force to animpacted body. Localized compression of a flexible foam decreases thearea over which force is transmitted and therefore increasing pressureand damage of the impact. A foam that is too hard for a specific type ofimpact will not compress sufficiently and will decelerate the impactedbody too quickly. This results in excessive resistance in the earlyphase of impact and will not compress enough to prolong distance or timeof impact. Therefore, advances in impact foams continue to be soughtthat exhibit light weight, resilience, and desirable impact response toa variety of impact types.

Silicone resins are common and used in various applications due to theirsuperior properties in heat and chemical resistance, electricalinsulation properties, water repellency and safety to humans.

SUMMARY

A polyurethane foam material comprising a polyurethane, a polymerizationreaction initiator, and a polymerization reaction accelerator isprovided. The polyurethane is formed from an isocyanate and a polyol.The polymerization reaction initiator is an isoprenoid compound.

The foam material can optionally further include a polyorganosiloxanepolymer. The polyorganosiloxane polymer is cross-linked to thepolyurethane.

These foams can be layered to create a polyurethane andpolyurethane/polyorganosiloxane composite material. The layeredcomposite can include a modified open cell flexible polyurethane foamlayer with cross-linked rubber polymers fused with a second hard foamlayer consisting of a modified hybrid polyurethanefoam/polyorganosiloxane/rubber foam mixture. Additional optionalcomponents can be added to further enhance the foam materials and aremore fully outlined in the following detailed description.

There has thus been outlined, rather broadly, the more importantfeatures of the invention so that the detailed description thereof thatfollows may be better understood, and so that the present contributionto the art may be better appreciated. Other features of the presentinvention will become clearer from the following detailed description ofthe invention, taken with the accompanying drawings and claims, or maybe learned by the practice of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is schematic bottom view a protective helmet that illustratesone configuration having a composite polyurethane foam material with thepolyurethane/polyorganosiloxane foam insert.

FIG. 1B is a side cross-sectional view of the insert of FIG. 1A.

FIG. 1C is a schematic bottom view of a protective helmet thatillustrates another configuration having a foam insert in accordancewith one aspect.

FIG. 1D is a side cross-sectional view of the insert of FIG. 1C.

FIG. 2 is a perspective view of a car bumper that illustrates one aspectof the foam material having a composite structure.

FIG. 3A is a front view of a protective groin cup that illustrates oneaspect of use for the polyurethane foam material with thepolyurethane/polyorganosiloxane foam.

FIG. 3B is a side cross-sectional view of FIG. 3A.

These drawings are provided to illustrate various aspects of theinvention and are not intended to be limiting of the scope in terms ofdimensions, materials, configurations, arrangements or proportionsunless otherwise limited by the claims. Reference will now be made tothe exemplary embodiments illustrated, and specific language will beused herein to describe the same. It will nevertheless be understoodthat no limitation of the scope of the invention is thereby intended.

DETAILED DESCRIPTION

While these exemplary embodiments are described in sufficient detail toenable those skilled in the art to practice the invention, it should beunderstood that other embodiments may be realized and that variouschanges to the invention may be made without departing from the spiritand scope of the present invention. Thus, the following more detaileddescription of the embodiments of the present invention is not intendedto limit the scope of the invention, as claimed, but is presented forpurposes of illustration only and not limitation to describe thefeatures and characteristics of the present invention, to set forth thebest mode of operation of the invention, and to sufficiently enable oneskilled in the art to practice the invention. Accordingly, the scope ofthe present invention is to be defined solely by the appended claims.

Definitions

In describing and claiming the present invention, the followingterminology will be used.

The singular forms “a,” “an,” and “the” include plural referents unlessthe context clearly dictates otherwise. Thus, for example, reference to“an initiator” includes reference to one or more of such materials andreference to “reacting” refers to one or more such steps.

As used herein with respect to an identified property or circumstance,“substantially” refers to a degree of deviation that is sufficientlysmall so as to not measurably detract from the identified property orcircumstance. The exact degree of deviation allowable may in some casesdepend on the specific context.

As used herein, a plurality of items, structural elements, compositionalelements, and/or materials may be presented in a common list forconvenience. However, these lists should be construed as though eachmember of the list is individually identified as a separate and uniquemember. Thus, no individual member of such list should be construed as ade facto equivalent of any other member of the same list solely based ontheir presentation in a common group without indications to thecontrary.

As used herein, “soft foam” means a foam that is softer than the “hardfoam.” As used herein, “hard foam” means a foam that is harder than the“soft foam.” These expressions should be interpreted flexibly andrelative to one another regardless of absolute hardness. The use of softand hard is not meant to describe the compressive strength of thematerial, nor the materials ability to resist deformation and should notbe interpreted in such a manner. Rather the terms soft and hard aremerely included to designate the relationship between the two types offoam presented within the disclosure.

As used herein, “polyurethane” means a polymer composed of a chain oforganic units joined by urethane links. Polyurethanes are formed byreacting an isocyanate with a polyol both of which contain an averagetwo or more functional groups per molecule. By reacting two or moreisocyanate groups per molecule (R—(N═C═O)n₂) with a polyol containing onaverage two or more hydroxyl groups per molecule (R—(OH)n₂) in thepresence of a catalyst, a flexible polyurethane foam is produced.

As used herein, “silicone rubber” or “siloxane rubber” is an elastomercomposed of silicone polymer containing silicon together with carbon,oxygen and hydrogen. Siloxane rubbers are often one or two partspolymers, are stable, and resistant to extreme temperatures andenvironments from −55° C. to +300° C. The siloxane rubber is a flexiblepolymer, and compared to a polyethylene backbone, is much more flexiblesince the bond length are longer and they can move farther and changeconformation easily.

Silicone is an adhesive gel or liquid and must be cured, vulcanized orcatalyzed. Silicone rubber can be cured in three ways: a—by aplatinum-catalyzed addition cure system, a condensation cure system, anda peroxide cure system or an oxime cure system. In the embodiment ofthis disclosure, a platinum-catalyzed cure system is used where twoseparate components must be mixed to catalyze the polymer: one componentcontains a hydride—and a vinyl-functional siloxane polymer is mixed witha platinum complex creating an ethyl bridge between the two. Thisplatinum based system has a high tear strength and dimensionalstability, high resistance to high temperatures, and is safe for theenvironment, nontoxic and odorless.

In another embodiment of this disclosure, tin-based cure system can beused as a substitute in the presence of an alkoxy cross-linker andsilicone polymers. Once the cross-linker is hydrolyzed, it exposes ahydroxyl group at its end which then participates in a condensationreaction with another hydroxyl group attached to the actual polymer. Thepresence of tin catalyst is not necessary though it does speed up thecuring/crosslinking process. Similarly, a peroxide based system can beused. Other polysiloxane rubber polymers such as polydimethylsiloxanes,organofunctional polydimethylsiloxanes or siloxane polyether co-polymerscan be used as substitute.

Concentrations, amounts, and other numerical data may be presentedherein in a range format. It is to be understood that such range formatis used merely for convenience and brevity and should be interpretedflexibly to include not only the numerical values explicitly recited asthe limits of the range, but also to include all the individualnumerical values or sub-ranges encompassed within that range as if eachnumerical value and sub-range is explicitly recited. For example, anumerical range of about 1 to about 4.5 should be interpreted to includenot only the explicitly recited limits of 1 to about 4.5, but also toinclude individual numerals such as 2, 3, 4, and sub-ranges such as 1 to3, 2 to 4, etc. The same principle applies to ranges reciting only onenumerical value, such as “less than about 4.5,” which should beinterpreted to include all of the above-recited values and ranges.Further, such an interpretation should apply regardless of the breadthof the range or the characteristic being described.

Any steps recited in any method or process claims may be executed in anyorder and are not limited to the order presented in the claims.Means-plus-function or step-plus-function limitations will only beemployed where for a specific claim limitation all of the followingconditions are present in that limitation: a) “means for” or “step for”is expressly recited; and b) a corresponding function is expresslyrecited. The structure, material or acts that support the means-plusfunction are expressly recited in the description herein. Accordingly,the scope of the invention should be determined solely by the appendedclaims and their legal equivalents, rather than by the descriptions andexamples given herein.

Flexible Polyurethane—Soft Foam

This invention describes a flexible polyurethane foam formed from aunique composition of polyurethane (formed from an isocyanate and apolyol), a polymerization reaction initiator, and a polymerizationreaction accelerator. The initiator, and accelerator along with theoptional gelling agent, surfactant, and reinforcement filler are addedat room temperature as described in the specification.

Flexible polyurethane foam is manufactured as a product of a reaction oftwo raw materials, a polyol and a diisocyanate. When the raw materialsare combined, the reaction forms bubbles and the mixture expands.Although a separate blowing agent can be added the polymerizationreaction forms gases which contribute to forming the foamed product. Thepolyol and the polyfunctional isocyanate react to form polyurethane. Thegeneral reaction is shown below.

Each R¹ group has multiple isocyanate groups; thus, there is a highdegree of cross-linking in the polyurethane. Once complete, the rawmaterials are converted to a usable product.

Water is used as a blowing agent and catalyst in the present invention.However, suitable catalysts that can be used include:

-   -   a—Tertiary amines such as        N-methylimidazole,N-methylmorpholine,N-ethylmorpholine,triethylenediamine,triethylamine,tributylamine,triethanolamine,pen        tamethyldiethylenetriamine,pentamethyldipropylenetriaamine,dimethylethanolamine        and bisdimethylaminodiethylether    -   b—b—organotins such as water, acetone, pentane, liquid carbon        dioxide, HFC, HCF, CFC and methylene chloride.

In one embodiment of the present disclosure, a methylene bisphenylisocyanate (MDI) solution (commercially available as Polytek®) and amixture of polyether polyol can be mixed in a volume ratio of 1 to 2, toform polyurethane. Although other proportions can be suitable, thismixture can often comprise about 66% to about 87% by volume of thecomposition.

In another embodiment of this disclosure, the polyurethane foam iscomposed of methylene bisphenyl isocyanate, polyether polyol, naturalpine rosin, a polymerization reaction accelerator, analginate-containing hydrogel powder, fumed silica, charcoal or carbonblack, natural and synthetic rubber, polysulfide polymer, silk fibroinand hydoxyethyl cellulose.

The polyurethane foam material provides improved impact absorption andresilience while being light weight. This foam can have a shore hardnessvalue from 15 to about 40 A, and most often about 30. Further, thismaterial can be configured for use in a variety of devices. Thepolyurethane foam is capable of repeatedly absorbing shock withoutstructural damage.

Flexible Polyurethane Foam-Polyorganosiloxane Co-Polymer—Hard Foam

In one embodiment of this disclosure, the polyurethane foam material,described above is combined with an ingredient of a polyorganosiloxanecomposition. This results in a flexible and tough open cellpolyurethane/polyorganosiloxane foam with a shore hardness value ofabout 85, although about 50 to about 100 can be used. To create thepolyorganosiloxane, the polyurethane foam from above, is combined with apolyorganosiloxane, a polymerization catalyst, typically platinum,benzyl alcohol, a polymerization reaction initiator, and apolymerization reaction accelerator. In one embodiment thepolyorganosiloxane can be Soma-Foama 15 (Smooth-On Inc) and compriseabout 5% by volume. In another embodiment the catalyst can compose about10% by volume.

The polyorganosiloxane used has two amine or hydroxyl groups attachedvia a linkage group to one end of the compound. This end group iscapable of cross-linking with polyurethane, various other polyols, andcross-linker molecules. The organosiloxane has one or moreisocyanate—reactive functional groups. The polyorganosiloxane componenthas the following formula:

where R¹ is a terminal group, R² and R³ can be organic groups such asmethyl, ethyl and phenyl groups, the inorganic silicon-oxygen backbone nis about 1000-5000 repeating units long, LINK is a linking group (shownabove as un-bracketed SiR²R³ group), and R^(a) is—hydroxyl or aminegroup. In some cases, the organic side groups (R² and R³) can be used tolink two or more the silicon-oxygen backbones together. One example of alinking group is the alkylene group which may have one or more sulfuratoms, nitrogen or oxygen atoms substituted for a backbone carbon atom.In one embodiment the R¹-terminal group may be a trialkylsilyl group(R₃Si-groups). In another embodiment the le terminal group can beRR₂Si-groups. One specific embodiment of the RR₂Si-group is abutyldimethylsilyl (BuMe₂Si—) group.

The silicone atom will have at least one bond to an organic molecule andthis is commonly referred to as siloxane polymer (—R—SiO—). Foradhesives, the most common organic group found on the silicon atom ismethyl. Other functional groups, such as hydroxyls and amines can bepresent based on the specific cure chemistry of a formulation. Thepolymerization catalyst can be platinum, although other catalyst curesystem can be used such as a Tin based cure system, a peroxide basedcure system or an oxime based cure system. A platinum cure system isused in this disclosure which allows the cure reaction to be acceleratedby heat in the presence of only ppm of platinum. Silicone polymers haveweak mechanical properties when cross-linked; therefore, in the hardfoam, the silicone polymers are reinforced with fillers such as fumedsilica and polysulfide polymers.

In the hard foam, the hydrophilic silicone elastomer is cross-linkedwith another polymeric silicone and with polyurethane polymer. Thisallows the silicone polymers, Si—H group to react with the free hydroxylgroup of a polyurethane polymer and a cross-link Si—O-polyurethane isachieved. In the case of a Si—OH group or Si—NH₂ group, reaction with anelectrophilic group on a polyurethane compound such as isocyanate, estergroup or other electrophilic group will result in a cross-linkedelastomer-polyurethane composition.

A silicone elastomer containing at least one functional group (Si—H,Si—OH, NH₂, Si—C═C group) is mixed with a polyurethane containing atleast one reactive functional group (OH, NH₂, methacrylate or olefinvinyl group) to form a cross-linked silicone elastomer/polyurethanepolymeric material.

The resultant cross-link structure produced by the chemical interactionof isocyanate group of polyurethane chain and the hydroxyl group ofpolymethylphenylsiloxane is a hydroxyl functionalizedpolyorganosiloxane.

Where L represents either a bond or a linking group selected fromdivalent hydrocarbons having 1 to 10 carbon atoms. An exemplaryembodiment of the hydroxyl functionalized polyorganosiloxane with anexemplary divalent hydrocarbon linking group is shown below.

The hydroxyl functionalized polyorganosiloxane is combined with apolyurethane polymer to form a di-functional or multifunctionalpolyorganosiloxane/diisocyanate cross-linked polymer. The example of thedi-functional or multifunctional polyorganosiloxane/diisocyanatecross-linked polymer below does not exemplify the linking group butrather lists the linking group as L.

Polyurethane Polymer

Di-Functional or Multifunctional Polyorganosiloxane/DiisocyanateCrosslinked Polymer

This polymeric material is then cross-linked with a Thiokol polysulfidepolymer, cis 1,4 polyisoprene, polybutadiene,polystyrene-block-polybutadiene-block-polystyrene and silk fibroin inthe presence of ethylene glycol, abietic acid, diterpenes, N-hydrogel(Polytek), fumed silica (Polytek), carbon black, sulfur, stearic acidand zinc oxide. The entire mixture is mixed vigorously at roomtemperature inside a chemical hood and poured directly into a mold inthe shape of the desired product. The reaction is immediate andviolently exothermic with repeated rise and collapse of the foammixture. The mixture rises two times until the final third rise at whichpoint the exothermic polymerization chain goes to completion. Once thisfinal third rise occurs, polymerization proceeds to completion and thehard open cell polymerized foam takes its final shape and density atroom temperature. In one embodiment the polymerization reaction processrequires 2-6 hours to cure and where the polyurethane foam is composedof methylene bisphenyl isocyanate, polyether polyol, and isocynate, andcombined to the polyorganosiloxane, with a natural pine rosinpolymerization reaction initiator, a polymerization catalyst, apolymerization reaction accelerator, and the composition furtherincludes alginate-containing hydrogel powder, fumed silica, carbonblack, and hydoxyethyl cellulose. To improve tear strength of the finalproduct, a polysulfide polymer solution containing carbon black,2-ehylhexyl diphenyl phosphate and polysulfide polymer from Smooth—onInc is added to the mixture at 8 volume %.

Polyurethane and Polyurethane/Polyorganosiloxane Foam Composite Material

In certain embodiments the polyurethane foam (described above) and thepolyurethane/polyorganosiloxane composition (also described above) arecross-linked to one another. In one embodiment the layers may beadjacent to each other. In another embodiment one layer can be fully orpartially surrounded by the other layer. In yet another embodiment, thelayer can involve a combination of a fully or partially surrounded layerand additional adjacent layers. The actual layering will vary based onthe desired product and the shape of the mold.

In order to create the combined layers, one layer is polymerized tocompletion in a mold, then the other layer is chemically fused to thefirst layer. The fusion occurs naturally because of polymercross-linking between the polyurethane foam and thepolyurethane/polyorganosiloxane composition. The end product is aone-piece foam composed of a polyurethane portion and apolyurethane/polyorganosiloxane portion. The differing portions can bearranged as adjacent layers and/or as a composite structure havingvarious shapes. If the desired product contains a combination layer,then after the first layer is cured a cutting machine can be used toaccurately cut and allow for removal of a portion of the first curedlayer. The removed portion can then be filled with the second layer andallowed to cure. In some embodiments a water jet cutting machine can beused to accurately cut and allow for removal of the first layer.

In one embodiment the polyurethane/polyorganosiloxane composition ispoured into the mold first and allowed to cure. Then the polyurethanefoam is added to the mold and allowed to cure. This creates apolyurethane/polyorganosiloxane outer layer and a polyurethane innerlayer. In another embodiment the polyurethane foam is added to the moldfirst and allowed to cure. Then the polyurethane/polyorganosiloxanecomposition is poured into the mold and allowed to cure. This creates apolyurethane outer layer and a polyurethane/polyorganosiloxane innerlayer.

In one embodiment the polyurethane foam composition comprises from about70 wt. % to about 85 wt. % of the material and the polyorganosiloxanecomprises about 8 wt. % to about 25 wt. % of the material. In anotherembodiment, the polyurethane foam has a density of about 4 lbs/ft³ andthe polyurethane/polyorganosiloxane foam has a density of about 10lbs/ft³. Although variations can be made, the composite foams can have ahard foam to soft foam hardness ratio from about 1.25 to about 7, insome cases about 2 to about 4, and in one specific aspect about 2.8.

The two fused layers can be used as an impact protective device. Whenused in impact protective devises the fused layers help to severelyreduce concussion, skull and brain injuries. Exemplary uses aredescribed in detail below. This layered foam combination can be appliedto the fabrication of the helmet (FIG. 1A through 1D), car bumper (FIG.2A and 2B), and to a groin cup (FIG. 3A and 3B).

In yet another alternative aspect, the polyurethane foam material canfurther include as an addition a polysulfide rubber polymer capable ofcrosslinking. To improve tear strength of the final product, apolysulfide polymer solution containing carbon black, 2-ethylhexyldiphenyl phosphate (a plasticizer) and polysulfide polymer fromSmooth-on Inc is added to the polyurethane and to thepolyurethane/polyorganosiloxane mixture at 8 volume %. When added, thepolysulfide polymer can further crosslink with the polyurethane andpolyorganosiloxane to create apolysulfide/polyorganosiloxane/polyurethane foam of high resiliency andtear strength.

Although variations can be made, the polyurethane portion can comprisefrom about 70 to about 86 vol % of the material. Similarly, thepolyorganosiloxane can often comprise from about 5 to about 25 vol % ofthe material. Further, the polysulfide polymer solution can oftencomprise about 5 to about 25 vol % of the material. Of particularinterest are compositions having from 80 to 86 vol % polyurethane, 7 to10 vol % polyorganosiloxane, and 7 to 10 vol % polysulfide.

Initiators and Accelerators

During the formation of the polyurethane foam and thepolyurethane/polyorganosiloxane foam composition a polymerizationreaction initiator and a polymerization reaction accelerator is used.The concentrations of polymerization reaction initiator andpolymerization reaction accelerator used in the formulations will varydepending upon the desired use for the foams. The embodiments herein arepresented solely as examples and should not be thought of as limitingthe disclosure.

Initiators

In this invention, the polymerization reaction initiator is anisoprenoid compound. Non-limiting examples of suitable initiatorsinclude abietic acid (a diterpene), camphor (a monoterpene), menthol (amonoterpene), natural liquid tree rubber (a polyisoprene), amyrin (apentacyclic triterpene), and combinations thereof. Initiators ofinterest include abietic acid, butadiene, styrene-butadiene-styrenepolymer and natural rubber.

Abietic acid (also known as abietinic acid or sylvic acid) is an organiccompound that occurs widely in trees and is a primary component of resinacid. Abietic acid belongs to the abietane diterpene group of organiccompounds, which are derived from four isoprene units, and have themolecular formula, C₂₀H₃₀O₂. Diterpenes form the basis of biologicallyimportant compounds such as retinol, retinal, and phytol. Thesediterpenes are carboxylic acids and initiate polymerization reactionsdue to active hydroxyl and hydrogen groups. The high polarity of thediterpene, abietic acid also permits compatibility with polyurethanepolymers. Due to hydrogen bonding interactions with other polymers inthe reaction, diterpene molecules contribute to further reinforcement ofthe polyurethane chain by supplemental cross-linking and long chainpolymer formation. The greater the hydroxyl content in the diterpenecompounds, the more hydrogen bonds between the diterpene and theisocyanate group. Hydrogen bonds between a diterpene (abietic acid) andan isocyanate can function as a physical cross-link at room temperatureto provide higher shear and cohesive strength and an increase in heatresistance.

Abietic acid can be obtained from Pinus kesiya royle (Khasi pine), Pinusstrobus (Eastern white pine), Pinus insularis (Southern pine), Pinussylvestris (Scots pine), Pinus ponderosa (Ponderosa pine), Pinuscontorta (lodgepole pine), and other sap extracts. Abietic acid can beobtained from pine rosin, also called colophony or Greek pitch, in asolid form of resin obtained from tree pine. Rosin is the nonvolatileportion of the oleoresin of members of the pine family and is theresidue left over after the isolation of turpentine. Pine rosin has aprimary chemical composition including methyl sandaraco pimaric, methylisopimaric, methyl palustric, methyl dehydroabietic acid, methylabietic, methyl neoabietic, and methyl merkusis acids. The highestcomponent in pine rosin is methyldehydroabietic acid (27-28%).

Reactive hot melt of filtered liquid Pine or Lodge Pole rosin containingabietic acid can be added to the composition at about 2% by volume. Atroom temperature, rosin is soft, sticky and can be brittle but meltswhen heated at around 85° C. Commercial abietic acid is available and isa glassy partly crystalline yellowish solid that melts at temperaturesas low as 85° C. and can be purchased and used as a substitute for pinerosin abietic acid. Suitable ranges for the reaction initiator includefrom about 2% to about 6% by volume, from about 4% by volume to about 5%by volume or from about 2% to about 10% by volume.

Accelerators

Further, a polymerization reaction accelerator is combined with themixture described above. Non-limiting examples of suitable acceleratorsinclude charcoal, activated carbon, diamonds, fullerenes, graphites,coke, coal, carbon black and combinations of these materials.Accelerators of interest include activated hardwood carbon, charcoal,and carbon black.

The preferred accelerators for the polyurethane foam are activatedhardwood carbon and charcoal. Activated carbon is carbon that has beentreated with oxygen, and is a highly porous material and extremely highsurface area. Activated pure hardwood carbon behaves as accelerator inthe polymerization mix by decreasing the time of the cross-linkingreaction. It also works as a strong filler-matrix interaction. Ifcharcoal is used as an accelerator, C₇H₄₀ can be used. Charcoal is alight black residue consisting of 85.5% to 98% carbon and residual ash.Regardless, specific types of charcoal can vary and suitable variationscan include, but are not limited to, lump charcoal, pillow shapedbriquettes, hexagonal Sawdust Briquette charcoal, extruded charcoal,Japanese charcoal and combinations of these materials. Each charcoaltype contains varying amounts of hydrogen and oxygen.

In one example, the accelerator for the polyurethane/polyorganosiloxanecomposition is carbon black. Carbon black is a para-crystalline carbon.In addition to being used as an accelerator, carbon black can be used asa filler.

When added to the composition, the polymerization reaction acceleratorcan comprise from about 2% to about 3% by volume, and in some cases fromabout 1% to about 7% by volume.

Optional Additives

The polyurethane foam and the polyurethane/polyorganosiloxane foam canoptionally be prepared with a gelling agent, emulsification controlagent, a reinforcement filler, rheology modifiers, slip agents,emollients, humectants, or any combination of these additives. Theconcentrations of optional gelling agent, emulsification control agent,reinforcement fillers, cross-linkers and reinforcement polymers usedwill vary depending upon the desired use for the foam. The embodimentsherein are presented solely as examples and should not be thought of aslimiting the disclosure.

Gelling Agent

Gelling agents are thickeners that form a gel, dissolving in the liquidphase as a colloid mixture and forming a weakly cohesive internalstructure. There are many suitable gelling agents. Non-limiting examplesof suitable gelling agents include: alginate containing hydrogel powder,acacia, alginic acid, bentonite, Carbopols® (now known as carbomers),carboxymethyl cellulose. ethylcellulose, gelatin, hydroxyethylcellulose,hydroxypropyl cellulose, magnesium aluminum silicate (Veegum®),methylcellulose, poloxamers (Pluronics®), polyvinyl alcohol, sodiumalginate, tragacanth, hyaluronan, polyethylene, carrageenans,polypropylene glycol, agar and polyvinylpyrrolidone, polyacrylic acid,hydrocolloid polyesters, chitosen, collagen, xanthan gum, andcombinations thereof.

Though each gelling agent has unique properties, some gelling agents aremore soluble in cold water than in hot water; others require a“neutralizer” or a pH-adjusting chemical to create the gel after thegelling agent has been wetted in the dispersing medium; most require24-48 hours to completely hydrate and reach maximum viscosity andclarity. Gelling agents can typically be used in concentrations fromabout 0.5% to about 10% by volume and from about 4% by volume to about6% by volume depending on the agent.

One preferred gelling agent is alginic acid containing hydrogel powder.For example, Hydrogel-N powder (commercially available as Polytek®),contains a mixture of magnesium carbonate, alginic acid, sodiumpyrophosphate, and calcium sulfate, and can be added to the polyurethanemixture at room temperature at a volume ratio of about 4% to about 6% byvolume, and in some cases about 2% to about 10% by volume at roomtemperature. Once the gelling agent is added to the mixture, polarhydrophilic groups are hydrated upon contact with water. The networkthen swells and exposes the hydrophobic groups, making the hydrophobicgroups capable of interacting with water. This swelling process byinteracting with the water molecules is then opposed by covalent orphysical cross-links during gelation.

Hydrogel polymers can serve as chain extenders with the help of ethyleneglycol and cations such as Mg²⁺ and Ca²⁺. Urea linkages are formed bythe reactions between—NCO groups of the MDI bisphenyl isocyanate andwater or —COO group of the alginic acid present in the hydrogel mixture.This chemical bonding further contributes to cross-linking and chainextension in the polymerization reaction.

Surfactants-Emulsifying Control Agents

Surfactants can be added to polyurethane and topolyurethane/polyorganosiloxane to emulsify the liquid components,regulate foam cell size, stabilize cell structure to prevent collapseduring polymerization, and to fill sub-surface voids. Variousemulsification control agents can exhibit advantages such as use inrecycling, cost reduction, mechanical properties and acoustic capabilityenhancement. Non-limiting examples of emulsification control agents caninclude fumed silica, silicone oil, nonylphenol ethoxylates,polydimethylsiloxane-polyoxyalkylene, polyethylene terephthalate, carbonnanotube, calcite, dolomite, calcium carbonate, and any combinationthereof. One preferred emulsification control agent is fumed silica(commercially available as Polytek®), a synthetic amorphous silicondioxide. Emulsification control agents can be added to the polyurethanemixture at about 4% to about 6% by volume, from about 4% to about 8% byvolume, and in some cases about 2% to about 10% by volume at roomtemperature.

Reinforcement Fillers

Reinforcement filler can be added to the polyurethane foam and/or thepolyurethane/polyorganosiloxane foam to enhance creep resistance andfoam elastic modulus of the foams. Reinforcement fillers are capable ofcross-linking and contribute to the increased resilience, toughness, andcomprehensive strength of the material. Examples of such fillers includehydroxyethyl cellulose polymer, hydroxypropyl methyl cellulose,cellulose acetate, cellulose nitrate, hydroxyethyl methyl cellulose,ethyl cellulose, methylcellulose, natural tree rubber latex, syntheticrubber (i.e. polybutadiene), and hot-melt branchedPolystyrene-block-polybutadiene, 30% styrene, 80% diblock, polysulfidepolymers and combinations thereof.

A cellulose fiber is composed of micro-fibrils where the cellulosechains are stabilized laterally by inter and intra-molecular hydrogenbonding as well as hydrogen bonding to the isocyanate group and othernewly formed polymers. Such hydrogen bonding serves as furtherreinforcement fillers in polyurethanes. In one embodiment hydroxyethylcellulose polymer is used as the reinforcement polymer. The hydroxyethylcellulose polymer is a modified, water-soluble polymer made by reactingethylene oxide with alkali-cellulose. Hydroxyethyl cellulose can beadded from about 0.5% to 2% by volume. Natural tree rubber latex can beused at about 1% by volume as a substitute or in conjunction withcellulose. In another embodiment the reinforcement filler can compriseabout 0.2 wt. % about 4 wt. % of the material. As a general guideline,reinforcement fillers can comprise about 0.2% to 10% by volume of thepolyurethane foam material. In some embodiments the reinforcement fillercan gave rise to novel and functional polymers and co-polymers.

Cross-Linker

If desired, the polyurethane foam and/or thepolyurethane/polyorganosiloxane polymer hybrid foam composition can beformed in the presence of a cross-linker. Non-limiting examples ofsuitable cross-linkers include ethylene glycol, zinc oxide,sulfur,1,4-butanediol, 1,6-hexanediol, cyclo-hexanedimethanol,hydroquinone bis(2-hydroxyethyl)ether (HQEE), diethanolamine,diisopropanolamine, triethanolamine and tripropanolamine andcombinations thereof. When the previously described polymerizationmixture is mixed in the presence of ethylene glycol, unique and novelpolymer polyols can be produced, which then serve as chain-extenders andcross linkers to the isocyanate chain. Such a composition can have adensity of about five pounds per cubic foot, although other densitiescan be achieved based on variations of foaming agents and other factors.

It is notable that toluene diisocyanate, primarily used generally as achemical intermediate in the production of polyurethane products,hexamethylene diisocyanate (HDI) and isophorone diisocyante (IPDI) areexcluded from the composition in this invention eventhough they can beused as a substitute for 4,4′ Methylene bis(phenylisocyanate) to producepolyurethane. In this invention, 4,4′ Methylene bis(phenylisocyanate),MDI, is used.

Reinforcement Polymers

A reinforcement polymer can optionally be used to cross-link thepolyurethane backbone to the polyurethane/polyorganosiloxane co-polymer,other polyols and to each other. The reinforcement polymer can be chosenfrom: polysulfide polymer rubber, natural rubber, synthetic rubbers suchas polybutadiene and polystyrene-block-polybutadiene-block polystyrene,pure silk fibroin and combinations thereof. Where latex allergies are aconcern, natural rubber can be omitted from the formulations.

Rubber Reinforcers

Further reinforcement can be achieved by further cross-linking thepolyurethane foam composition and/or the polyurethane/polyorganosiloxanecomposition with a combination of liquid polysulfide polymer rubber, hotmelt natural latex rubber (melted at 350° F.), liquid polybutadienerubber and hot melt styrene-butadiene-polystyrene rubber (melted at 375°F.). The art of using a combination of natural and synthetic rubbercontributes directly to the toughness and resilience of the polymerizedend product and dramatically increases the load absorbing capacitygenerated by an impact force.

It is well known that the physical properties of elastomeric polymericcomposition are improved by cross-linking or vulcanization as is thecase of cross-linking natural rubber with sulfur. Available commercialelastomeric compositions such as polybutadiene, acrylonitrile-butadienecopolymer and styrene-butadiene copolymer have been modified to containcarboxyl groups distributed randomly along the length of the polymerchain. Cross-linking of these elastomers in polyurethane foamcomposition and/or the polyurethane/polyorganosiloxane composition occurby exposing the carboxyl group to zinc oxide and stearic acid in themixture. Cross-linking of these molecules to thepolyurethane/polyorganosiloxane co-polymers and to each other gives riseto novel large and long chain polymers that contribute to the highstrength, resilience and impact energy absorption of the foam describedin this invention.

Polysulfide Rubber

Polysulfides are a class of chemical compounds containing chains ofsulfur atoms and can also be used in connection with the compositionsherein. The polysulfide can be included as a mixture with thepolyurethane, or as a separate adjacent layer. Two main classes exist:anions and organic polysulfides. Anions have the general formula S_(n) ²and are the conjugate bases of hydrogen polysulfides H₂S_(n). Organicpolysulfides have the formula RS_(n)A where R is an alkyl or aryl (i.e.phenyl group). Polysulfide polymers can be synthesized by condensationpolymerization reactions between dihalides and alkali metal salts ofpolysulfide anions.

n Na₂S₅ +n ClCH₂CH₂Cl→[CH₂CH₂S₅]_(n)+2n NaCl

Polysulfide polymers are also prepared by the addition of polysulfanesto alkenes,

2RCH═CH₂+H₂S_(x)→(RCH₂CH₂)₂S_(x)

Sodium polysulfide, in which n has a value of around 4 has been used inthe preparation of rubbery synthetic organic molecules called Thiokols.These molecules are formed by ring-opening polymerization reactions andpossess long chains in which polysulfide groups alternate with smallorganic groups capable of forming two covalent bonds. These Thiokolmolecules can be converted by heating with Zinc oxide into toughresilient materials used to make lining of storage tanks and hoses andin other applications requiring resistance to chemical and physicalattack. Thiokols have also been used as solid fuels for rockets. Inaqueous solution, these molecules have been used as protective coatingfor wood, metal and concrete surfaces.

A typical Thiokol method of polysulfide synthesis is shown below:

and the average structure of the liquid polysulfide polymer produced bysuch a reaction is as follows:

HS—(C₂H₄—O—CH₂—O—C₂H₄—S—S)_(n)—C₂H₄—O—CH₂—C₂H₄—SH

This polymer has terminal mercaptan (or thiol) groups and also hasdisulphide linkages within the backbone as used in this embodiment.These terminal mercaptan groups of liquid polymers are easilycross-linked by means of epoxide resins, inorganic or organic oxidizingagents and in this invention, it is crosslinked to the isocyanates. Theresult may be expressed as follows:

Furthermore, reacting a thiokol polysulfide polymer (Smooth-onpolysulfide polymer 68611-50-7) which has 3 to 5 sulfur atom permolecule with an isocyanate like MDI and with various polymers describedherein including but not limited to polyoligosiloxane, natural andsynthetic rubber in the presence of a cross-linker leads to theformation of novel polymers within the polyurethane foam that contributeto a higher tear strength as observed in this embodiment.

Natural Rubber

Pure Natural rubber elastomers from the tree, Hevea brasiliensis,consists of polymers of the organic compound isoprene (cis-1,4polyisoprene). This rubber can be melted at 350° F. in a melting furnacein a chemical hood and reactive hot melt is added at 2% by volume to thepolyurethane foam composition and/or the polyurethane/polyorganosiloxanecomposition before the addition of MDI. Inpolyurethane/polyorganosiloxane composition, zinc oxide, stearic acidand sulfur are added to the mixture at 0.2% by volume before theaddition of polyorganosiloxane and MDI. The Cis-1,4 polyisoprene iscapable of cross-linking to other polyols, to thepolyurethane/polyorganosiloxane co-polymer and to each other via sulfurcross-linking at temperature close to 150° C. during the polymerizationreaction. This reaction contributes to the increased elasticity andrigidity to the final hard and soft product.

Cis-1,4 Polyisoprene (Polymers in Pure Natural Rubber)

Vulcanized Rubber Chemical Structure

Above is vulcanized rubber with the addition of sulfur at 150° C. duringthe polymerization reaction of mixture. In applications where thereexist latex allergy concerns, natural rubber may be omitted from thecomposition and only synthetic rubber can be used.

Synthetic Rubber

Synthetic rubber polymer, is any type of artificial elastomersynthesized from petroleum byproducts (monomers). Styrene-butadienerubbers are derived from the copolymerization of 1,3 butadiene andstyrene as used in this disclosure. These can be substituted withsynthetic rubber prepared from isoprene (2-methyl-,3-butadiene),chloroprene (2-chloro-1,3-butadiene and isobutylene (2-methylpropene)cross-linked with a small quantity of isoprene. These products can thenbe mixed in various proportions to create products with a wide range ofmechanical, physical and chemical properties which could be used assubstitutes or additions to the synthetic rubber/s used in thisdisclosure.

In one embodiment of this invention, a platinum silicone rubber is usedthat has been modified with a reactive hydroxyl group capable ofcross-linking with the polyol/polyurethane and rubber polymers. Inanother embodiment, a synthetic rubberpolystyrene-block-polybutadiene-block-polystyrene (styrene 30 wt.%)—sigma Aldrich is heated at 375° F. in a melting furnace and the hotmelt is added at a 2 volume % to the polyurethane and/orpolyurethane/polyorganosiloxane foam before the addition ofpolyoligosiloxane and MDI. This synthetic rubber is capable ofcross-linking to the polyurethane backbone,polyurethane/polyorganosiloxane co-polymers, to other polyols, and othersynthetic and natural rubber present in solution. By doing so, it addsrigidity and resilience and increases dramatically the compressivestrength of the hard and soft foam.

Polystyrene-Block-Polybutadiene-Block-Polystyrene

In addition, a second synthetic rubber is used. Liquid and water solublehydroxyl terminated polybutadiene (Sigma—MW 3000)) capable ofcross-linking is added to mixture 1 and 2 at a concentration of 4 volume%. The liquid polybutadiene is composed of: 72% cis -1,4; 27% trans-1,4;and 1% vinyl. The liquid polybutadiene is capable of cross-linking thepolyurethane backbone, to the polyurethane/polyorganosiloxaneco-polymer, to other polyols, and to rubber polymers present insolution. The addition of polybutadiene directly contributes torigidity, compressive strength, resilience of the final hard and softproduct.

Silk Protein

Silk consists of two main proteins, sericin and fibroin. Fibroin is aninsoluble protein made by spiders, the larvae of Bombyx mori silkworm,other moths, and insects. In one embodiment of this disclosure, fibroinderived from the cocoon of the Bombyx mori silkworm is used. Silk fibershave exceptional strength. The strength occurs because of the layers ofanti-parallel beta sheets. The primary structure of the silk fibron is arecurring sequence of poly(Gly—Ser—Gly—Ala—Gly—Ala).

The high glycine and alanine content of each beta sheet allows forseveral beta sheets to be tightly packed with one another. The betasheets are arranged so that the crystals alternate in alignment fromsheet to sheet. The beta sheets are held together by hydrogen bonds thatform between the individual sheets. Hydrogen bonds are weak bonds andnot well known for their strength. It is the gradual failure of thehydrogen bonds in a slow and uneven manner that gives silk itsconsiderable elasticity; this allows silk to bend and stretch before itbreaks.

Purified silk fibroin in a liquid solution from different insect specieshas different amino acid arrangements; however most insect silks containa common primary structural pattern. Therefore, while differences inarrangement may vary the location of the hydrogen bonds and the specificproperties of the silk, any insect silk can be used as a substitute forBombyx mori fibroin in this invention.

In one embodiment of this disclosure, the fibroin silk protein can becross-linked to the polyurethane backbone, thepolyurethane/polyorganosiloxane backbone, other polyols and/or tonatural and synthetic rubber polymers and co-polymers. When fibroin iscross-linked to the structure of the polyurethane foam or thepolyurethane/polyorganosiloxane foam the foam materials exhibit anincrease in resilience and strength.

In another embodiment of the disclosure liquid fibroin is used tofurther increase the tensile strength and rigidity of the polyurethaneor the polyurethane/polyorganosiloxane material. Specifically, liquidsilk fibroin (which can be acquired from Silktap Inc.) is dissolved insolution at 3% by volume and added to the polyurethane foam. Liquid silkfibroin can also be dissolved in a solution at about 1% to about 2% byvolume and be added to the polyurethane/polyorganosiloxane material.

As used, in this disclosure the liquid silk fibroin was stored at 4° C.and used within two weeks. Using liquid silk fibroin quickly isimportant because the degree of breakage of the peptide chain ispositively correlated with the storage time.

If the fibroin is added to either the polyurethane or thepolyurethane/polyorganosiloxane composition along with MDI, urethanelinkages are formed between the fibroin and the polyurethanepre-polymer. These urethane linkages further increase the mechanicalstrength and thermal stability of the composition. In this disclosure,the polyurethane linked fibroin polymers improve the mechanicalproperties and provide higher thermal stability to the modified polymersof the polyurethane.

Emollient/Humectants

In one embodiment, the polyurethane foam and/or thepolyurethane/polyorganosiloxane foam can include an emollient orhumectant. Example emollients or humectants, include, but are notlimited to include: hyaluronic acid, glycerin, glyceryl triacetate,sugar polyols, urea, and the like. In one embodiment of the disclosure,hyaluronic acid may be used to improve the tactile response and feel onsurfaces of a final product. As a general guideline humectants cancomprise from about 0.05% to about 4% by volume of the polyurethane orpolyurethane/polyorganosiloxane foam compositions.

Stabilizers

In certain embodiments, it may be desirable to use a stabilizer whencreating the foam compositions. Non-limiting examples of suitablestabilizers can include xanthum gum. Such stabilizers can comprise about0.5% to about 5% by volume of the polyurethane and/orpolyurethane/polyorganosiloxane foam compositions.

Colorants

As yet another option, colorants can be added to the polyurethane foamand/or the polyurethane/polyorganosiloxane foam compositions. Suchcolorants can include pigments, dyes, or other colored materials. Forexample, polycolor dyes (e.g. Polytek®) can be added to the mixtureduring the polymerization reaction to create a colored foam, exemplarybut not limiting foam colors include; blue, red or yellow . As a generalguideline, colorants can comprise from about 0.01% to about 5% by volumeof the composition. The exact amount will vary, depending on desiredcolor intensity.

Novel Polymer Polyols

In one embodiment the disclosure, the polyurethane foam material iscomprised of: about 3 volume % pine rosin; about 2.7 volume % activatedhardwood carbon or charcoal C₇H₄₀; 5.5 volume % Hydrogel-N (Polytek®);about 6-8 volume % fumed Silica (Polytek®); about 0.5-1 volume %hydroxyethyl cellulose; 4 volume % of liquid butadiene (Sigma); 2 volume% of styrene-butadiene-styrene hot melt (375° F.); 2 volume % of naturallatex rubber hot met (350° F.); 8 volume % of polysulfide Thiokolpolymer; and 0.2-0.5 volume % of natural pure silk fibroin (5%weight/volume solution from Silktap Inc, Cambridge Mass.).

In another embodiment the disclosure, thepolyurethane/polyorganosiloxane foam material is comprised of: about 3volume % pine rosin; about 2.7 volume % carbon black; 5.5 volume %Hydrogel-N (Polytek®); about 6-8 volume % fumed Silica (Polytek®); about0.5-1 volume % hydroxyethyl cellulose; 4 volume % of liquid butadiene(Sigma); 2 volume % of styrene-butadiene-styrene hot melt (375° F.); 2volume % of natural latex rubber hot met (350° F.); 8 volume % ofpolysulfide polymer; and 0.2-0.5 volume % of natural pure silk fibroin(5% weight/volume solution from Silktap Inc, Cambridge Mass.).

The above formulations when mixed at room temperature give rise to novelpolymer polyols. These novel polymer polyols quickly bind to theisocyanate backbone of the polyurethane foam, to theisocyanate/polyoligosiloxane backbone of thepolyurethane/polyorganosiloxane foam, and to each other, which resultsin intermediate and extensive cross-linking between the compositions.

The novel polymer polyols formed by the polymerization process above,increase the load bearing capacity of the low density and highresiliency of the flexible polyurethane and of thepolyurethane/polyorganosiloxane foam and add toughness to themicrocellular foam structure. In other words, the varied and novelpolymer polyols that become chemically bonded to the polyurethanebackbone of the polyurethane foam and to thepolyurethane/polyorganosiloxane backbone of thepolyurethane/polyorganosiloxane foam contribute to the unique hightensile strength, elongation, tear resistance and impact absorption.

Exemplary Uses

The disclosed polyurethane foam material andpolyurethane/polyorganosiloxane mixtures have a wide and usefulapplication. These foams are flexible and comfortable when in contactwith vulnerable areas of the human body, are protective from impactdamage in an automobile and can be used in a variety of sportsactivities. These foam layers can be used separately or in combination.If desired they can be infused and/or coated with all weather-waterrepellant and fire resistant sealant.

When used in combination, theses foams work together to absorb impactshock. During a single or repeated impact, deformation of the open cellpolyurethane foam material occurs in which a portion of the softsegments, the polyol group, which is covalently bonded to the hardsegment of the polyurethane polymer, isocyanate, is stressed byuncoiling. As a result, the hard segment, i.e. isocyanate, becomesaligned in the stress direction. This reorientation of the hard segmentand extensive hydrogen bonding with the chain extender and cross-linkersdescribed above contribute to high tensile strength, elongation, andtear resistance values of the polyurethane foam materials. Thepolyurethane foam and polyurethane/polyorganosiloxane foam combinationcan be formed in the shape of an impact absorption device. Exemplarydevices are provided in further detail below.

Protective Helmets

In protective helmets and helmet inserts the polyurethane andpolyurethane/polyorganosiloxane foams can be fused together to form aprotective shell inside the helmet. In one embodiment thepolyurethane/polyorganosiloxane foam is the outside layer. This outsidelayer is fused and cross-linked to the inner polyurethane foam. Inanother embodiment the polyurethane foam is the outside layer and iscross-linked to an inner polyurethane/polyorganosiloxane foam. In yetanother embodiment the polyurethane and polyurethane/polyorganosiloxanefoam can both exist in one of the layers. FIG. 1A shows a helmet 100which includes an outer shell 102. An inner liner 104 can provideadditional insulation and comfort to a wearer. A composite liner 106 caninclude an outer composite layer 108 characterized by a first foam 110providing structural shape and a second foam 112 acting as areinforcement filler foam. Each of the first and second foams can beindependently selected from the polyurethane foam and thepolyurethane/polyorganosiloxane foam. The structural shape can bechambered as illustrated, although other shapes such as triangular,circular, trapezoidal, or the like can also be used. The composite linercan also include an inner foam layer 114 which acts as a comfort layerand also provide protection. The inner foam layer can be formed of anyof the foams disclosed herein, although other foams such as, but notlimited to, in conjunction and/or in any combination of the following:ethylene vinyl acetate (EVA), polyesters such as polyethyleneterephthalate (PET) and polycarbonate, ethylene-propylene co-polymers,polyamides, polyethers, aramids co-polymers, and the like can also beused. FIG. 1B shows a cross-section view of the composite liner 106.

FIG. 1C shows another helmet 150 having a rigid hard shell 152 with anoptional inner comfort layer 154. A polyurethane foam insert 156 can beoriented within the hard shell 152. In this configuration, the softinsert 156 can have a single foam layer 158 which is formed of at leastone of the polyurethane foams (polyurethane or polyurethane/polysulfidefoam as described in this invention). An optional reinforcement layer160 can be placed and crosslinked along an outer surface of the singlefoam layer 158. The reinforcement hard layer is composed ofpolyurethane/polyorganosiloxane foam orpolyurethane/polyorganosiloxane/polysulfide foam as described in thisinvention). A fabric or other suitable layer can then allow securing tothe hard/soft shell (e.g. hook-and-loop, or the like) to the helmetinner surface of the rigid hard shell. An inner perforated layer 162 canalso be oriented on an inner surface of the foam layer to provideadditional moisture wicking, breathability, or other benefits to thewearer. Non-limiting examples of the inner perforated layer withventilation holes can include a combination of cotton, polyester meshfabric, flexible polyurethane and a blending of natural and syntheticfibers that repel moisture, pulling it off the skin and into the fabric.FIG. 1D illustrates the insert 156 as a removable insert which can bereplaced if damaged or excessively worn.

When foam blocks of varying thickness and length are added and placedstrategically inside the polycarbonate/fiberglass or carbon fiber hardshell helmet over a space extending from the forehead to the back of thehead, the impact force is absorbed by the fibrous open cell polymersduring compression. As a result, the damaging impact from perpendicularand rotational forces takes longer to reach the user's head thusenhancing absorption and dissipation. This decreases or eliminates thechances of a brain concussion during sports activities. The two layeropen cell system polymers in their three-dimensional arranged structureare extremely capable of absorbing high and repeated impacts withoutdeformation.

Transportation Vehicles

The polyurethane and polyurethane/polyorganosiloxane foam containing alland any combination of accelerators, initiators, gelling agents,emulsification control agents, reinforcement fillers, cross-linkers,reinforcement polymers, emollients, humectants, stabilizers, andcolorants described herein can be used as a protective layer inautomobiles, recreation vehicles, watercraft and aircraft. When used inbumpers, doors and outer rims, the foam materials can be used to absorbenergy from high impact crashes and protect the vehicles occupants. Itcan also be used as an outer casing in protecting flammable liquidcompartments in all facets of aerospace and in transportation includingbut not limited to mobility vehicles such cars, trains, boats andairplanes.

In one exemplary embodiment, the foam can be poured into blocks 4 ft inlength, 5.5 inches in height and 4 or 3 inches in width (approximately 8to 10 lbs). These blocks can then be used as the front and rear bumpersof a mobility vehicle or watercraft. The blocks are capable of absorbinghigh impact energy during high speed crash, are virtually indestructibleand capable of absorbing an repeated high energy impact forces. FIG. 2is an exemplary bumper configurations. In FIG. 2, the bumper 200 isformed of a polyurethane/polyorganosiloxane foam layer 202 that is thencut with a programmable software using a high speed water cutting jetmachine from Omax. The programmable software cut various geometriccircles and X shapes to allow room for the soft foam 204. Varyingprogramming can be utilized to cut the hard foam in different geometricshapes and size. In one embodiment, a 2 inch wide layer of X's is madeand the triangular voids are filled with the polyurethane foam. To fillthe void, the polyurethane foam is placed in a mold and as it is risingthe polyurethane/polyorganosiloxane foam is placed on top. This allowsthe polyurethane foam to fill the X space during the polymerizationprocess. The figures display an 1 inch wide hardpolyurethane/polyorganosiloxane foam on the outer edges that areinterconnected by columns 206 every 8 inches, with an inner layer of thepolyurethane foam. This device can also be manufactured with thepolyurethane foam as the outer layer and thepolyurethane/polyorganosiloxane foam as the inner layer depending on theparticular application, desired weight and energy absorptioncharacteristics.

In yet another embodiment, blocks of the polyurethane foam, thepolyurethane/polyorganosiloxane foam or blocks containing both of thesefoams can be created in varying length, width and shape to fit as acushion within doors of a vehicle or around the exterior of awatercraft. These foams will function as a cushion in the event of acollision. The foam blocks can be secured against a metal framework sothat the foam blocks can take, absorb and dissipate impact forces in acrash.

In yet another embodiment, the polyurethane foam, thepolyurethane/polyorganosiloxane foam or blocks containing both of thesefoams can be created and placed between train cars. The foams can beused to absorb an extremely high impact force associated with acollision. This can provide protection among adjacent train compartmentsby preventing these compartments from compounding each other.

Protective Padding

The flexible open cell two layer foam material containing a polyurethanelayer and a polyurethane/polyorganosiloxane layer containing theaccelerator, initiator, gelling agent, emulsification control agent,reinforcement filler, cross-Linkers, reinforcement polymers (includingpolysulfide polymers), emollients, humectants, stabilizers, andcolorants and any combination thereof described in this invention canalso be configured for use in contact/collision sport activities asprotective padding. The two layer system can be changed into afour-layer system where alternating polyurethane andpolyurethane/polyorganosiloxane layers can be used to absorb extremelyhigh impact energy. The flexible light weight one or two layer systemcan be molded for use in any area where impact on the body often occurssuch as: helmets, jackets, shoulder pads, elbow pads, thigh pads, kneepads, shin pads, groin pads and any combination thereof. As yet anotherexample, FIG. 3A and 3B show a groin cup 300 made with the two layerpolyurethane and polyurethane/polyorganosiloxane composition. FIG. 3Bshows the groin cup 300 having an inner polyurethane layer 302 and anouter harder layer 304 (e.g. polyurethane/polyorganosiloxane). Anoptional inner fabric layer 306 can be formed of breathable fabric orother suitable material. This groin cup is designed to withstand andabsorb high impacts while protecting the human body during high impactsports such as in ultimate fighting sport, football, hockey, baseball,or other sports having risk of injury.

The flexible foam described herein has also been shown to be veryeffective in shock absorption when configured as a full length sole ofvarying thickness and length cut in the shape of an interior or exteriorof a shoe.

Durability

It is important to note that the fused soft foam layer and the hard/softfoam layer used for bumpers, helmets or groin cups maintains its shapeafter a high load force is exerted upon it. For example, when a 6 ton X5BMW runs over these products, the foam flattens under the sheer loadsbut returns to its original shape without any damage: i.e. revertingback to the shape of a helmet or a groin cup instantly once load isdissipated. The bumper layer is capable of holding the entire weight ofa car with slight indentation to accommodate the weight absorption butwithout any deformation or damage.

EXAMPLES Example 1 Polyurethane Foam

In one embodiment, the polyurethane foam composition was created bymixing; 20 grams of activated hardwood carbon (60 ml by volume) with 30grams of Hydrogel-N (Polytek®) (120 ml by volume), 24 grams of FumedSilica (Polytek®) (240 ml by volume), 2 grams of hydroxyethyl cellulose(5 ml by volume), and 0.1 ml of colorant (Polytek) to the polyol mixturecontaining 2000 ml of liquid solution of polyol (part B-Polytek) at roomtemperature. Then, 60 ml of melted and filtered Lodgepole or Pine rosin(200° C.), 10 ml of melted natural rubber (350° F.), 10 ml of meltedpolystyrene-block-polybutadiene-block-polystyrene (Styrene 30 wt%—Aldrich) (375° F.), 120 ml of polybutadiene synthetic rubber, 240 mlpolysulfide polymer solution, and 3 ml of pure silk fibroin solution(Silktap) were added to above mixture at room temperature and stirred inthe presence of 3 grams each of sulfur, stearic acid and zinc oxide.This mixture was then placed in a vacuum chamber for 5 minutes andallowed to sit idle for 10 minutes under negative pressure. Followingthis, 1000 ml of polymethylene bis phenylisocyanate (MDI) and butylbenzyl phthalate solution (Foam Part A—Polytek) was then added to theentire mixture above and stirred vigorously for 10 seconds. The wholemixture is then poured into mold where polymerization reaction beginsimmediately to form a novel modified soft foam of a 4 lbs/cubic feetdensity.

Example 2 Polyurethane/Polyorganosiloxane Foam

In another embodiment, the polyurethane/polyorganosiloxane foamcomposition was created. First, 2000 ml of the polyurethane foammixture, from above, was made without the addition of MDI solution andwithout pouring the mixture into a mold. Then, 160 ml ofpolyorganosiloxane platinum catalyst solution (Soma Foama PartA-smooth-On Inc) was added to that mixture and stirred. A separatemixture containing 1000 ml of MDI and butyl benzyl phthalate solution(Polytek part A) and 80 ml of polyorganosiloxane (Soama Foama PartB-Smooth-On Inc) is then combined and added to the mixture above andstirred vigorously for 10 seconds. The whole mixture is poured into amold. The polymerization reaction is immediate, exothermic and give riseto hard foam with extremely high tensile strength, toughness andcompression resistance with far better flame retardant quality thantraditional polyurethane foam and polystyrene used for impactabsorption.

Modifications to Examples 1 and 2

Example changes include using different isocyanate, polyol and/orsilicone product, isoprenoid, rubber, fibroin and other reinforcers,gelling agents and additives with different methods, volumeconcentration and density. Concentrations by volume of the above can bevaried to form a more hardened or softer foam. For harder flexible foam,6-10% by volume of melted pine rosin can be added without affecting thepolymerization foaming reaction. Alternatively, lower concentrations ofpine rosin, e.g. 2.5% by volume, can be used for softer flexible foam.In addition, varied concentration by volume of activated hardwoodcarbon, fumed silica, hydrogel-N, cellulose, natural and syntheticrubber, silk fibroin and polysulfide polymers can be used with differentconcentration of melted pine rosin. Variations of these components canalso give rise to softer or harder polyurethane foam to be used fordifferent protective commercial applications.

In addition different variations and concentrations ofpolyorganosiloxane in conjunction with polyurethane, polysulfidepolymers, natural and synthetic rubber and silk fibroin can be used toaffect cell size, hardness, resiliency and toughness of the hard andsoft foam for specific applications. It is worth noting that Soma Foama25 (25 lbs per cubic feet density) instead of 15 (15 lbs per cubic feetdensity) or in conjunction with Soma Foama 15 can be used to furtherstrengthen the hard foam. Other variations in chemical structure of thesilicon polymers can be used as substitute with similar and/or differingcharacteristics of the final foam product.

Impact Force Demonstrations Bumpers

A vehicular bumper 5.5 inches high×4 inches wide×4 ft in length bumperfrom FIG. 2 was created using the formulations in examples 1 and 2. Thebumper was only 12 lbs pounds in weight and was attached to the frontbumper of a 6 ton SUV using industrial strength Velcro. The SUV,traveling at speed of 30 miles per hour hit the back bumper of anothercar at rest. Neither car had any resultant structural damage.

Padding—Impact Force

The polyurethane foam composition was created using the formulation inexample 1. The foam was molded into the shape of a 4 inches high×12inches wide×36 inches long soft foam pad. A full 50 lb plastic PolandSpring Bottle was dropped from 18 ft height above onto the foam. Thewater bottle did not rupture or have any structural damage following thedrop. The polyurethane foam absorbed all of the energy on impact and didnot deform.

Repeated Impacted Forces

The polyurethane foam composition above was created using theformulation in example 1. The foam was repeatedly hit using unlimitedimpact from an industrial hammer at high velocity. The foam did notdeform. The tear strength of the foam appears to be at least 20 to 30times stronger than the regular flexible polyurethane foam in the markettoday.

Helmets

A polyurethane foam polyurethane/polyorganosiloxane foam combination wascreated using the formulations in the examples above. The layers weremolded such that the polyurethane/polyorganosiloxane foam was exteriorto the polyurethane foam layer. This composition was molded as a 1 lb inweight insert for a helmet. (See FIG. 1A). Upon testing the insert wasshown to dull the effect of an impact to the level that concussionresulting from a rotational force impact might be severely reducedand/or eliminated.

A similar foam design can be molded for use in a motorbike helmet (about1 lb in weight) instead of the usual EPS used commercially today (0.5lbs weight). (See FIG. 1B). Similar benefits can be realized withmotorbike helmets.

The foregoing detailed description describes the invention withreference to specific exemplary embodiments. However, it will beappreciated that various modifications and changes can be made withoutdeparting from the scope of the present invention as set forth in theappended claims. The detailed description and accompanying drawings areto be regarded as merely illustrative, rather than as restrictive, andall such modifications or changes, if any, are intended to fall withinthe scope of the present invention as described and set forth herein.

What is claimed is:
 1. A polyurethane and polyorganosiloxane foammaterial comprising at least one layer of cross-linkedpolyurethane/polyorganosiloxane foam including: a) a polyurethane formedby reacting an isocyanate and a polyol; b) a polyorganosiloxane having across-linkable functional group; c) a polymerization catalyst; d) apolymerization reaction initiator, said initiator being an isoprenoidcompound; and e) a polymerization reaction accelerator; wherein thepolyurethane and the polyorganosiloxane are cross-linked to one anotherthrough the cross-linkable functional group.
 2. The material of claim 1,wherein the polyurethane is present in a first portion, and thepolyorganosiloxane is present in a second adjacent portion whichportions are cross-linked together to form a composite material.
 3. Thematerial of claim 2, wherein the first portion has a density of about 4lbs/ft³ and the second portion has a density of about 15 lbs/ft³.
 4. Thematerial of claim 1, wherein the isocyanate is methylene bisphenylisocyanate and the polyol includes polyether polyol.
 5. The material ofclaim 1, wherein the isocyanate is methylene bisphenyl isocyanate andthe polyol includes polyether polyol, the isoprenoid is natural pinerosin, and the material further includes alginate-containing hydrogelpowder, fumed silica, charcoal, and hydroxyethyl cellulose.
 6. Thematerial of claim 1, wherein the polyurethane comprises from about 66wt. % to about 87 wt. % and the polyorganosiloxane comprises about 8 wt.% to about 25 wt. % of the material.
 7. The material of claim 1, whereinthe polymerization reaction initiator is selected from the groupconsisting of: abietic acid, camphor, menthol, natural liquid treerubber, amyrin and combinations thereof.
 8. The material of claim 7,wherein the polymerization reaction initiator is abietic acid derivedfrom pine rosin.
 9. The material of claim 1, wherein the polymerizationreaction initiator comprises from about 2 wt. % to about 10 wt. % of thematerial.
 10. The material of claim 1, wherein the polymerizationreaction accelerator is selected from the group consisting of charcoal,activated carbon, diamonds, fullerenes, graphites, coke, coal, andcombinations thereof.
 11. The material of claim 1, wherein the materialfurther comprises a gelling agent, an emulsification control agent, areinforcement filler, or a combination thereof.
 12. The material ofclaim 11, wherein the material includes the gelling agent which is amember selected from the group consisting of alginate-containinghydrogel powder, methylcellulose, xanthan, carboxymethyl cellulose,hyaluronan, polyethylene, carrageenans, polypropylene glycol, agar andpolyvinylpyrrolidone, polyacrylic acid, hydrocolloid polyesters,chitosen, collagen, and any combination thereof.
 13. The material ofclaim 11, wherein the material includes at least one emulsificationcontrol agent and wherein the at least one emulsification control isselected from the group consisting of fumed silica, silicone oil,nonylphenol ethoxylates, polydimethylsiloxane-polyoxyalkylene,polyethylene terephthalate, carbon nanotube, calcite, dolomite, calciumcarbonate, and any combination thereof.
 14. The material of claim 11,wherein the material includes at least one reinforcement filler and atleast one reinforcement filler is selected from the group consisting ofhydroxyethyl cellulose polymer, hydroxypropyl methyl cellulose,hydroxyethyl methyl cellulose, ethyl cellulose, nitrocellulose,cellulose acetate, methylcellulose, natural tree rubber latex, syntheticrubber (polybutadiene), hot-melt branched polystyrene blockpolybutadiene, polysulfide polymers, and any combination thereof. 15.The material of claim 14, where the at least one reinforcement fillercross-links with the polyurethane foam.
 16. The material of claim 11,wherein the at least one reinforcement polymer is selected from thegroup consisting of natural rubber, synthetic rubber such aspolybutadiene and polystyrene-block-polybutadiene-block-polystyrene,polysulfide polymers and pure silk fibroin and combinations thereof. 17.The material of claim 1, wherein the polymerization catalyst isplatinum.
 18. The material of claim 1, wherein the cross-linker isselected from the group consisting of ethylene glycol, zinc-oxide,sulfur, 1,4-butanediol, 1,6-hexanediol, cyclo-hexanedimethanol,hydroquinone bis(2-hydroxyethyl)ether (HQEE), and combinations thereof.19. The material of claim 1, further comprising a polysulfide.
 20. Thematerial of claim 1, wherein the material is formed in a shape of animpact absorption device.
 21. The material of claim 20, wherein theshape is at least one of a bumper cushion of a vehicle, a cushion withina door of a vehicle, and a protective padding.
 22. The material of claim21, wherein the protective padding is selected from the group consistingof a helmet, shoulder pad, elbow pad, thigh pad, knee pad, shin pad,groin pad, shoe sole, and any combination thereof.